Guanidinylating Peptide Sequencing for Single-Molecule Protein Detection
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Solution Overview
Problem
Current protein sequencing methods, such as mass spectrometry and Edman degradation, lack single molecule sensitivity and spatial information, while immunohistochemistry provides limited scalability and sequence information.
Innovation Solution
Development of sequencing reagents comprising reactive groups, capture-binding moieties, and linkers, specifically using guanidinylating agents, to form covalent bonds with N-terminal amino acids for sequencing polymeric analytes like peptides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mass spectrometry is used for protein sequencing, then protein identification and quantification based on mass/charge ratio is enabled, but single molecule sensitivity is not achieved and spatial information is lost
Solution Approach 1:
The patent introduces a solid support with a capture moiety as an intermediary to immobilize and concentrate single protein molecules. This mediator enables the protein to be detected and sequenced at single-molecule levels while maintaining spatial information, resolving the contradiction between measurement precision and quantity detection.
Solution Approach 2:
The patent transitions from solution-based mass spectrometry to a spatially-resolved solid support system. By anchoring proteins to a solid support with specific capture moieties, the method adds spatial dimensionality, enabling single-molecule detection while preserving location information that was lost in traditional MS approaches.
2Measurement precision
If Edman degradation is used for protein sequencing, then sequential N-terminal amino acid removal and identification is achieved, but throughput is low and harsh reaction conditions are required
Solution Approach 1:
The patent replaces the mechanical/chemical Edman degradation process with a enzymatic approach using proteases. This substitution eliminates the need for harsh acid and heat conditions, enabling milder reaction environments while maintaining sequencing capability and improving throughput through enzymatic efficiency.
Solution Approach 2:
The patent changes the reaction conditions from harsh (acidic, high temperature) to mild (neutral pH, ambient temperature) by using enzymatic cleavage. This parameter change enables the method to be compatible with sensitive analytes and improves overall productivity without sacrificing sequencing precision.
3Shape
If immunohistochemistry is used for protein identification, then spatial localization is achieved, but sequence information is excluded and scalability is limited
Solution Approach 1:
The patent merges the spatial localization capability of immunohistochemistry with the sequencing capability of mass spectrometry. By combining capture moieties for spatial anchoring with proteolytic sequencing, the method simultaneously provides both location information and amino acid sequence data, eliminating the information loss present in traditional IHC.
4Measurement precision
If traditional protein sequencing methods are used, then protein identification is achieved, but low copy-number proteins remain undetected
Solution Approach 1:
The solid support with capture moieties acts as a concentrator and mediator that enables detection of single low-abundance protein molecules. This intermediary system amplifies the signal from rare proteins, making them detectable against background noise and resolving the sensitivity issue for low copy-number proteins.
Solution Approach 2:
The patent segments the detection process into discrete steps: capture, immobilization, proteolytic cleavage, and detection. This segmentation enables systematic analysis of individual protein molecules, improving the ability to detect and quantify low-abundance proteins that were previously undetectable in bulk analyses.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-throughput, single molecule sequencing of proteins with spatial information, overcoming the limitations of existing methods by providing efficient and scalable protein identification.
Implementation Method 1
A reactive group configured to form a covalent bond with an N-terminal amino acid of a peptide
Data Source
AI summary
The present disclosure provides reagents and methods useful for single-molecule sequencing of proteins through use of a sequencing reagent of Formula I, IV, IV′, IV″, IV-A, IV-B, or V-C. The reagents and methods described herein provide for high-throughput single molecule and high efficiency protein and peptide sequencing in mild conditions allowing for high resolution investigation of complex biological systems.